The DNA diagnostic laboratory at San Francisco General Hospital is requesting continued funding as a Core laboratory that will provide DNA- based genotypic diagnoses for the Northern California Comprehensive Sickle Cell Center and serve as a diagnostic resource for other institutions. We will provide genotypic diagnoses for subjects in studies at the center and for patients whose clinical diagnosis cannot be determined readily using standard clinical testing, and will continue to develop improved methods for DNA diagnosis. Specifically, we will determine betas-globin and alpha-globin genotypes and beta-RFLP haplotypes of subjects to be enrolled in clinical and basic science studies at the Northern California Comprehensive Sickle Cell Center, which will be correlated with the information obtained in those studies. We will also provide genotype diagnoses for patients having difficult-to- diagnose hemoglobinopathies, including those for whom original diagnosis were not obtained before they were begun on chronic transfusion therapy, candidates for prenatal diagnosis whose mutations must be defined at the DNA level before prenatal diagnosis can be undertaken, and patients whose genotype diagnoses are obscured by complex interactions of multiple hemoglobinopathic genes. We will also continue to develop and adapt methods that offer advantages for DNA based diagnosis in sickle cell disease and other hemoglobinopathies. Methods that we are currently developing in our laboratory include direct sequence analysis of PCR product, denaturing gradient gel electrophoresis, single strand confirmational polymorphism, and gap PCR. These methods will provide greater breadth of diagnostic capabilities in our laboratory and may offer potential for replacing certain of the diagnostic method we currently employ. The availability of the sophisticated diagnostic methods used in this laboratory will complement and supplement the diagnostic abilities of the Core Hemoglobinopathy Laboratory.